4-Methylmorpholine → 3-[(N-Boc-Piperidin-4-ylmethyl)aminocarbonyl]benzoyl-2(S)-3-pyridylsulfonylamino-beta-alanyl-glycine benzyl ester

Participants

Reaction Steps

A solution of 31-1 (0.75 g, 1.5 mmol) in 1:1:1 THF/MeOH/H2O (15 mL) was treated with LiOH·H2O (0.37 g, 8.8 mmol). After 45 min. the solution was concentrated, diluted with water, washed with EtOAc. The aqueous layer was acidified to pH 2-3 with 10% KHSO4 and extracted with EtOAc. The organic layer was dried (Na2SO4), filtered and evaporated to give an acid which was dissolved in acetonitrile (3 mL) and treated with glycine benzyl ester·HCl (0.1 g, 0.5 mmol), N-methylmorpholine (0.11 mL, 0.98 mmol), and BOP reagent (0.26 g, 0.58 mmol) for 24 h. The solution was concentrated, dissolved in water and EtOAc and the layers separated. The organic layer was dried (Na2SO4), filtered and evaporated. Column chromatography (SiO2, 70% acetone/hexanes) gave 31-2 as a white solid.

Provenance & Evidence